Dorman 918-359 PCV Valve Diaphragm

Dorman 918-359 PCV Valve Diaphragm

Dorman 918-359 is an OE FIX PCV valve diaphragm for diesel crankcase ventilation systems on select Ford Super Duty trucks. It replaces the diaphragm inside the air separator assembly to address clogging from oil and carbon buildup without replacing the full separator box.

Compatible with 2011-2019 Ford F-250 Super Duty and 2011-2019 Ford F-350 Super Duty applications, this part supports proper crankcase pressure control and helps restore normal engine operation. The Dorman 918-359 is built with steel, rubber, and plastic components and includes a spring for the diaphragm assembly.

Key Features

• OE FIX replacement for the PCV valve diaphragm in the crankcase ventilation system
• Direct service part for select Ford Super Duty diesel engine air separator assemblies
• Replaces the diaphragm instead of the complete separator assembly
• Constructed from steel, rubber, and plastic materials
• Includes spring as part of the assembly
• Fits 2011-2019 Ford F-250 Super Duty and 2011-2019 Ford F-350 Super Duty

Detailed Description

The PCV valve diaphragm in diesel crankcase ventilation systems can become restricted by oil and carbon deposits over time. When that happens, the air separator assembly may no longer regulate blowby gases correctly, which can lead to excessive crankcase pressure and drivability concerns. Dorman 918-359 provides a targeted repair for the diaphragm portion of the system, helping reduce repair cost and downtime compared with replacing the entire separator assembly. This part number is a practical service solution for Ford F-250 Super Duty and Ford F-350 Super Duty diesel trucks in the listed model years.

This part cross-references Standard Ignition EOS5 for the same application.

Common Issues This Part Addresses

• Excessive crankcase pressure
• Oil leaks related to ventilation restriction
• High idle caused by crankcase ventilation problems
• Reduced engine performance from a clogged diaphragm
• Failure of the air separator assembly due to oil and carbon buildup

Installation Notes and Tips

Install on the engine air separator box assembly used in the listed Ford Super Duty diesel applications. Inspect the separator housing, diaphragm surface, and related ventilation passages for oil sludge or carbon deposits before installation. Confirm the vehicle year and model match the fitment listing for Dorman 918-359 before service.

Quality Assurance

Dorman engineers OE-style replacement parts to address common failure points with serviceable components. This diaphragm is intended as a direct repair solution for the specified Ford Super Duty crankcase ventilation system.